An image formation system which shows super high contrast photographic properties (particularly with a .gamma. value of 10 or more) is required in the field of graphic arts to obtain good image reproduction of continuous tone by dot images or reproduction of line images.
An image formation system has been desired which comprises developing a photographic material using a processing solution having an excellent storage stability to provide super high contrast photographic properties. By way of example, a system has been proposed which comprises processing a surface latent image type silver halide photographic material containing a specific acylhydrazine compound with a developing solution containing 0.15 mol/liter or more of a sulfite preservative and having a pH value of from 11.0 to 12.3 to form a super high contrast negative image with a .gamma. value of more than 10 as disclosed in U.S. Pat. Nos. 4,166,742, 4,168,977, 4,221,857, 4,224,401, 4,243,739, 4,272,606 and 4,311,781. This novel image formation system is characterized in that silver iodobromide or silver chloroiodobromide can be used in contrast to conventional super high contrast image formation methods in which only silver chlorobromide having a high silver chloride content could be used. Furthermore, the system has a comparatively good storage stability because it can contain a large amount of a sulfite preservative as opposed to the conventional lith developing solution which could use only a slight amount of a sulfite preservative.
On the other hand, a scanner and an image setter having an oscillating wavelength of from 600 nm to 700 nm have recently been widely propagated by the development of a laser and a light emitting diode, and the development of a super high contrast photographic material applicable to these power units has been strongly desired. Combinations of sensitizing dyes having preferred color sensitivities with hydrazine compounds are disclosed in JP-A-4-178644, JP-A-4-275541, JP-A-4-311946 and JP-A-5-224330 (the term "JP-A" as used herein refers to a "published unexamined Japanese patent application"); however, they are not yet satisfactory with respect to sensitivities, residual coloring (after processing), and fluctuations of the properties of photographic materials during storage.